72 ILLINOIS BIOLOGICAL MONOGRAPHS [390 



SPECIES OF TRICHIOCAMPUS 



1(2) Body with three pairs of longitudinal rows of blackish or brownish segmentally 

 arranged spots along subdorsal, supraspiracular, and subspiracular lines; tenth 

 abdominal tergum not entirely black but white except a pair of minute spots; head 

 light brown with brownish spots, with following parts dark brown : dorso-meson of 

 vertex, dorsal two-thirds of front, and vertex dorso-caudad of each ocellara including 

 gena; preclypeus whitish, other parts pale, including occiput between vertical 

 furrows; a row of brownish spots from mesothoracic to ultimate segment along each 

 side of dorso-meson; a row of larger spots along supraspiracular line from prothoracic 

 to penultimate segments; another row of much smaller spots along subspiraciJar 

 lines from mesothoracic to eighth abdominal segment; mesothoracic and metathoracic 

 subspiracular spots more than twice as large as supraspiracular spots of same seg- 

 ments; the former with circular white areas around the proximal end of setae; 

 prothoracic supraspiracular spots small and indistinct; third abdominal segment 

 with following setal map: 1, 3, 5, 1, 2, 5, 4, 8, 9-10, 8-9; tenth abdominal tergum 

 white, except a pair of minute spots; subdorsal spots not involving tubercles 2 and 3; 

 supraspiracular spot involving tubercles 4 and 5; subspiracular spot on caudal half of 

 subspiracular tubercle; maxillary palpi (2, 3), 1, 4; head in younger specimens black- 

 ish except near the mouth; body without spots; in older specimens, supraspiracular 

 spots appear first, then subspiracular, beginning with caudal segments, setae on tuber- 

 cles sometimes one or two less than in mature specimens; on Populus; length of 

 body, 12 mm.; width of head, 1.5-1.6 mm.; G-Onekama and Orono on oak, length of 

 body, 13 mm.; width of head, 1.7 mm., M-207. (The latter resembles the former 

 so closely and indistinguishably, altho its setae may be slightly fewer in number, 

 that they are considered as identical.) />aeiw/i« MacGillivray. 



2(1) Body with two pairs of longitudinal rows of blackish or brownish segmentally 

 arranged spots along supraspiracular and subspiracular lines; tenth abdominal 

 tergum entirely black; head blackish, with paler areas 3. 



3(4) Mesothoracic supraspiracular spots subequal in size to subspiracular spots; supra- 

 spiracular spots of abdominal segments not involving postsupraspiracular tubercles; 

 prothoracic supraspiracular spots minute and indistinct; preclypeus, labrum, and 

 genae blackish; metathoracic subspiracular spots with minute but distinct circular 

 whitish areas around proximal end of setae; head blackish, paler along vertical 

 furrows, epicranial arms, and postclypeus; body with a row of blackish spots from 

 mesothoracic to penultimate segment along supraspiracular and subspiracular lines; 

 tenth abdominal tergum black; third abdominal segment with the following setal 

 map: 1, 3, 3, 0, 2, 4, 4, 5-6, 8-9, 6-8; subspiracular spot involving few setae directly 

 ventrad of spiracles; head in younger specimens entirely blackish and spots on 

 subspiracular lines wanting; maxillary palpi, (2, 3), 1, 4; length of body, 18 mm.; 

 width of head, 1.3 mm.; on SalLx; Y-151-1-1,-151-1-3; M-100,-261. (The specimens 

 in the Maine collection are practically identical with my specimens except in the 

 number of setae on subspiracular and surpedal lobes, which may exceed the number 

 given byoneor two) /lo/cAice MacGillivray. 



4(3) Mesothoracic supraspiracular spots not subequal to but distinctly larger, twice or 

 more, than subspiracular spots; supraspiracular spots of abdominal segments in- 

 volving postsupraspiracular tubercles; prothoracic supraspiracular spots large and 

 distinct; preclypeus, labrum, and genae not blackish but pale brown; metathoracic 

 subspiracular spots without minute but distinct whitish circular areas around the 

 proximal end of setae; head black, paler along vertical furrows, epicranial arms, 

 clypeus, labrum, and genae; body with a row of blackish or brownish spots from 

 prothorax to penultimate segment along supraspiracular and subspiracular lines: 



